But what appears most intriguing about the case is the role of the American citizen, identified only as a confidential informant, who at some point was captured by U.S. authorities. The complaint also alleges that a second confidential source who travelled from Saudi Arabia to Iran and then to Pakistan corroborated information about the two Yemeni defendants. Prosecutors charge that both men took part in attacks on U.S. military forces in 2008 and also received al Qaeda training during a trip to Pakistan that year, Reuters reported. His story illustrates what many U.S. officials warn may be happening with other U.S. citizens leaving the country and hooking up with terror groups, such as Islamic State. Heim said Abbadi encouraged the American by showing him “a scar from a bullet wound that he sustained while fighting against United States military or Blackwater forces in Iraq.” He said Abbadi also showed the American “a clip on his Kalashnikov assault rifle that he had taken in Iraq as part of his ‘spoils of war.’” The three men would spend nights watching videos, including one “depicting jihadists celebrating after a successful attack,” Heim said in the complaint.

When the emir of his fighting group was wounded, the American became an instructor on battlefield first aid, and how to dress a wound and perform CPR. Then he returned to the battlefield and in June 2008, Heim said, was part of an Al Qaeda group that attacked an Afghan National Police Station and a mosque in Gardez, Pakistan.